This invention relates to a projector of light beams.
More specifically, the projector according to this invention is used for lighting television programs and outdoor or indoor public shows.
This type of the projector is structured to be able to emit a beam of light modified in amplitude, intensity, coloring and combined with optical effects capable of varying the shape of the beam emitted.
In order to be able to guarantee these features, the projector comprises a shell for containing and supporting the components which generate the light beam. The shell has a main longitudinal extension along a relative axis of longitudinal extension.
The shell is, normally, articulated to a support (usually configured in the form of a fork) to be able to rotate about at least a first axis transversal to the its longitudinal axis of extension, whilst the support is configured to be able to rotate about a second axis perpendicular to the axis of longitudinal extension to allow a series of coordinated positions designed to conveniently direct the light beam as a function of the lighting needs.
It should be noted that the components of the projector generating the light beam are positioned inside the shell and comprise, in the solutions currently known in the prior art, at least a light source positioned at a first end of the shell and connected to a source of energy for emitting the beam according to a direction of illumination parallel to the axis of longitudinal extension of the shell.
An outlet lens of the light beam is positioned at a second end of the containment shell and affects the passage of the light beam.
The projector also comprises a frame for connecting the two ends of the containment shell.
The frame supports a first optical body for focusing the light beam and interposed between the light source and the outlet lens; this first optical body is equipped with first means for movement along a wall of the frame for modifying its distance from the light source along a trajectory parallel to the longitudinal axis of the shell.
A second optical body for varying the focal length (or zoom) of the light beam is supported by the frame and interposed between the first optical body and the outlet lens. This second optical body comprises means for moving, in two directions, along the wall of the frame for modifying its position relative to the outlet lens (on one side) and the first optical body (on the other side) along a trajectory parallel to the longitudinal axis of the containment shell.
At least a third optical body defining, for example, but without limiting the scope of the invention, a prismatic lens generating an optical effect acting on the light beam (for example, splitting the light beam in several parts, or, depending on the position, variations of the outlet angle from the projector of luminous figures formed with the prismatic lens) and positioned inside the containment shell.
The third optical body, in one of the prior art solutions, is associated with, that is, articulated, to a supporting arm.
The supporting arm can rotate, selectively, between a non-operating position, wherein the third optical body is moved away from the first or second optical body and, therefore, from the light beam, and an operating position close to the first or second optical body wherein the third optical body is positioned along the trajectory of the light beam.
In a first prior art solution, the supporting arm of the third optical body is directly articulated to the frame of the projector in a stable position along the extension of the projector.
In two further prior art solutions the arm is articulated, to the first or to the second optical body.
In the first solution, the third optical body is positioned in such a way as to be interposed, in its operating configuration, always between the first and the second optical body.
In the second and third solution, the third optical body may be interposed, in its operating configuration, between the first and the second optical body or between the second optical body and the outlet lens of the light beam.
In these last two possibilities, the position of the third optical body is linked to the decision to connect the third optical body to the second optical body, upstream or downstream of the latter relative to the direction of the light source, or to the first optical body.
However, these three different solutions involve limitations or drawbacks to the operating capacity of the projector.
In the first solution mentioned above, in which the third optical body is fixed to the frame, the optical effect of the prismatic lens which can be obtained cannot be modified, that is, the outlet angle of the figure obtained is fixed and cannot be modified even by modifying the position of the first or second optical body.
In the second and third solution, that is, with direct connection between the first optical body or the second optical body with the third optical body, the latter again positioned at a fixed distance (center distance) relative to the optical body to which it is integral and again either downstream or upstream of them relative to the direction of emission of the light beam.
The fixed center distance between the third optical body and (again) one of the other two optical bodies does not allow modification/expansion of the effect which can be obtained from the prismatic lens which there would be adjusting the center distance or modifying the pre-eminence position (relative to the direction of emission of the light beam) between the three optical bodies.